At a press conference on Tuesday, Nehammer said six sites in inner-city Vienna were targeted and authorities were working on the assumption there were several more shooters working together.
He said it was unclear if the man and his group were part of a coordinated IS attack. Nehammer said while the first attack occurred near a synagogue, authorities were still assessing whether anti-Semitism was a motive.
Nehammer confirmed 15 people were hospitalised with injuries, including a police officer who was expected to recover. ORF said seven were fighting for their lives.
Footage showed gunmen dressed in white jumpsuits running through the Austrian capital’s streets while firing their weapons shortly after 8pm, Vienna time (Tuesday AEDT).
Heavily armed police swarmed the city centre and urged the public to hide inside restaurants and shops. Some video footage showed injured people bleeding outside a restaurant and being treated by shocked patrons.
Vienna’s chief rabbi, Schlomo Hofmeister, told British radio station LBC that he came out of the synagogue and onto the street after hearing gunshots and then saw men shooting at guests of bars and restaurants.
“The gunmen were running around shooting at least 100 rounds or even more in front of our building. People were jumping and running, falling over the tables, running inside the bars, followed by the gunmen also running inside the bars.
“We heard shots all over. Later on when the police arrived […] we heard them asking whether there were any injuries inside and people shouted out of the various bars ‘yes we have two here’, or ‘yes we have three here’.”
Franz Ruf, chief of public safety for police, said more than 1000 police and soldiers from terrorism and specialist teams were working in inner-city where barricades would remain in place.
He said Austria was working with neighbouring countries to establish “strong controls” on its borders amid the possibility the attackers would flee Austria.
Ruf added that more than 20,000 videos of the attacks had been uploaded to a special link, which was helping authorities identify the shooters.
“There are police actions underway,” he said, refusing to give more details as it could impede the manhunt.
Austrian Chancellor Sebastian Kurz said the attacks were “definitely” terrorism.
He said some people had been arrested and disarmed but several remained on the run. They were armed with automatic guns and “professionally prepared”, he added.
Nehammer encouraged families to keep their children at home on Tuesday, advised the inner-city would remain shut and told Vienna residents to avoid leaving home unless absolutely essential.
Upper Austrian police director Andreas Pilsl would not confirm to ORF if there were investigations underway in the state of Upper Austria. He told people in the state not to travel to Vienna.
“Because of the attacks in Vienna we have increased the presence of our forces […] the situation is dynamic, and we are supporting our colleagues in Vienna as much as we can.”
Nehammer said his thoughts were with the victims.
“When one of us is attacked, all of us are attacked,” Nehammer said.
The shooting took place hours before the midnight start of a nationwide lockdown, one of several being imposed in Europe to stop the spread of the coronavirus.
The area where the shooting took place is packed with bars and Vienna’s main temple, the Seitenstettengasse synagogue.
The president of the Jewish Religious Community in Austria, Oskar Deutsch, said the shooting had occurred “in the immediate vicinity” of the temple but it was closed at the time.
A spokesman for Vienna city police, Harald Soeroes, said police were searching for several co-attackers who remained at-large as part of the “hot phase” immediately following the shootings.
“It’s very, very important that every Vienna resident stays at home and observes public information. If you are in a location now, please stay there,” Soeroes said.
The shooting comes amid heightened tensions in Europe. A teacher was beheaded in an attack outside his school in Paris 16 days ago and last week a man beheaded a church worshipper and stabbed two others to death inside the Notre-Dame Basilica in Nice.
“We French share the shock and grief of the Austrian people struck this evening by an attack in the heart of their capital, Vienna,” said French President Emmanuel Macron.
“After France, a friendly country is attacked. This is our Europe. Our enemies must know who they are dealing with. We will not give up.”
Prime Minister Scott Morrison said Australia “condemns absolutely the cowardly terrorist attacks […] and we stand with the people of Austria as they, even at this time, are working through a very uncertain and fluid situation. We send our best and our support and our sympathies to all of them”.
“For Australians who are in Austria, I urge you to follow the instructions of local authorities and you can also ensure you’re updated through the Smartraveller website.
US President Donald Trump tweeted that “our prayers are with the people of Vienna after yet another vile act of terrorism in Europe”.
“These evil attacks against innocent people must stop. The US stands with Austria, France, and all of Europe in the fight against terrorists, including radical Islamic terrorists.
Police urged the public to not share footage of the attack on social media, fearing it may assist the attackers.
Bevan Shields is the Europe correspondent for The Sydney Morning Herald and The Age.
Michael is a state political reporter for The Age.